Alexander wilford hall



(No Model.)

A. W. HALL. PIANOFORTE.

I No. 501,226.

Patented July 1l, 1893. j.

I IH el" MMIV ,W AAW UNITED STATES PATENT OEEICE.

ALEXANDER YILEORD HALL, OF NEW YORK, N. Y.

PIANOFORTE.

SPECIFICATION forming part of Letters Patent No. 501,226, dated July 11, 1893.

Application filed October 12,1892. Serial No. 448,665. (Nomodel.)

To all whom it may concern:

Be it known that I, ALEXANDER WILEORD I-IALL, of the city of New York, in the State of New York, have invented a new and useful Improvement in Pianofortes, of which the following is a specification.

My improvement relates to the bridge, the attachment of the bridge to the soundboard, the means for confining the strings to the bridge and the means for connecting the strings to the iron plate commonly known as the hitch-plate.

To explain the nature and object of my improvement in the bridge I will first refer briefly to the usual bridge which is glued throughout its entire lengthto the sound-board, the soundboard and the bridge being thus stiffened so that their free vibration is prevented while a large portion of the sound-board on both sides of the bridge is rendered useless in the production of resonance when the strings are struck by the hammers. To give more elastic freedom to the bridge I cutaway the bridge at intervals throughout its length, the amount so cut away amounting in the aggregate to about one-half of the bridge, and I glue the intervening portions of the bridge to the sound-board in the usual way; and to those parts of the bridge remaining above where it has been cut away I attach arms of any suitable material, preferably elastic and resonant wood, extending on either side of the bridge for some distance, the outer ends being attached to the sound-board, the object of the said arms being to convey the vibrations of the strings through the bridge to distant portions of the sound-board and thereby to augment the sound.

To explain the nature and object of my improvement in means for confining the strings to the bridge I will first state that the usual methods of securing firm contact between the string and the Wood of the bridge are two. One of them is to leave the bridge above the level of the hitch points at the two ends of the string so that a considerable downward pressure is produced by the string on the bridge, but this is objectionable because it stiffens both the bridge and the sound-board. The other of said methods is to bend the string against the pins at the place of crossing the bridge, such pins being put slanting in opposite directions so as to direct the strain of thewireagainstthewoodofthebridge. Metal agraffes have also been used to secure the strings to the bridge but such agraffes prevent the string from touching the wood and also by their considerable weight tend to deaden the bridge and thus weaken the tone. According to my improvement I make the bridge at the surface where the strings cross it exactly level with the hitch points of the two ends of the strings, thus obviating the stiffening of the sound-board by the bearing of the string upon it; and in the bridge so constructed and arranged I use the pins slanting in the opposite directions in the usual way against the opposite sides of the string, but to secure complete contact between the string and the bridge I employ a channeled strip of metal which I place with its edges against the string and secured to the bridge by means of screws by which the said strip is made to clamp the string. This strip is preferably made of aluminium and as thin as practicable in order to obtain the desired result with the least posy sible weight.

The usual method of securing the strings to the iron plate or frame is to attach them directly to the said plate or frame by loops or eyes made in the strings and secured to what are known as hitch pins fastened in the plate. This method of attaching between two hundred and three hundred steel strings directly to the plate which is necessarily in close proximity to the bridge tends to stiffen the bridge and dead en the sound-board. To avoid this I employ short powerful coil springs one end of each of said springs being hitched to the pins in the plate and the other end being attached to the loop in the end of the string. The interposition of these springs beltween the string and the hitch pin and between the bridge and the hitch plate allows much greater vibratory freedom to the string, the bridge and the sound-board than the usual method.

My invention is illustrated in the accompanying drawings in which- Figure 1 is a front View of the frame and stringed parts of an upright piano-forte elnbodyin g iheimprovement, showing a sufhcient number of the strings to illustrate my invention.

Fig. 2 represents a transverse sectional ICO view of the bridge and part of the sound-board and shows the attachments of the bridge and the means for securingthe string thereto. Fig. 3 represents a section of part of the soundboard and a face view of the bridge and its attachments. Fig. 4 represents a longitudinal View partly in section of one of the springs employed to connect the strings with the hitch plate.

Similar letters of reference designate corresponding parts in all the igures.

A is the wrest plank and B what is known as the metallic plate.

a d are the shorter strings which are nearer the sound-board and a a are the longer strings which are over a a.

C is the sound-board.

D is the bridge for the shorter strings au.

D is the bridge for the longer strings a a.

My improved construction of the bridge is shown in Figs. 2 and 3 in which it will be seen that the portion'of the bridge next the sound-board is cut away or recessed at intel-vals c c leaving between the said intervals solid parts CZ which are attached to the soundboard by gluing. The solid parts CZ d and the recesses c c may be of equal length so that about half the bridge is in contact with the sound-board. The arms e e which proj ect from the bridges for the purpose of conveying the vibrationsof the string to distant parts of the sound-board are shown in Fig. l, but their connection with the bridge and the soundboard is better shown in Figs. 2 and 3. These arms may be of wood or metal, but I prefer to construct them of light strips of elastic resonant wood which are placed within the recesses c of the bridge and attached to the bridge by screwsfand the outer ends of which rest upon the sound-board and are attached thereto by screws g. These arms may extend right through the bridge and project therefrom on opposite sides as shown in Fig. 2, but I prefer to arrange them as shown in Figs. 1 and 3, each to project from one side only of the bridge, their arrangement being such that they alternately project from opposite sides of the bridge, though in parts where the bridge comes very close to the plate B as in the case of the bridge D (see Fig. l) the arms may be arranged on that side of the bridge only on which is the greater length of the strings.

E is the channel strip of metal which is screwed to the top or bearing face of the bridge with its edges, bearing on the strings by means of screws h h which pass through it and are screwed into the bridge. This channel strip is preferably arranged behind the pins t which are commonly employed to confine the strings to the bridge. The said strip has its lower or inner edges pressed down by the screws h h which are applied to `it at numerous short intervals in such manner as to embed the strings in the wood of the bridge thereby securing` the most direct contact while the weight of the said strip when made of aluminium will not perceptibly deaden the bridge or weaken the tone. Another objeet of this absolute contact is that after the piano is tuned and the screws 7L h set in the wood of the bridge, the strings will be so held that they will stay in tune much longer than in the ordinary piano-forte.

F F are the coil springs which connect the strings with the hitch pins j in the plate B. rlhese springs which require to be short in Order to avoid any material increase in the size of the piano-forte should have the maximum tension or strength with the minimum size and for this purpose I prefer to make them with the wire of which they are composed larger than the interior of the coil as I have found that otherwise a proper tension cannot be obtained within the limit of the space available in a piano-forte. The said springs are made with an eye or loop 7c at each end and one of the said eyes should have the end of the string looped into it and the other of the said eyes is intended to be hitched on to the pin j. The springs thus interposed between the hitch pin and that part of the string which rests on the bridge will allow greater vibratory freedom to the strings than when the strings are attached directly to the hitch pin, while the springs being of proper tensile strength, the proper tension of the strings is preserved.

What I claim as my invention is l. The combination with the sound-board and bridge of a piano-forte, of arms projecting from the bridge and having their outer ends attached to the sound-board at a distance from the bridge, substantially as and for the purpose herein set forth.

2. The combination with a piano-forte sound-board, of a bridge recessed atintervals in the part next the said board and provided on either side opposite said intervals with projecting arms the outer ends of which are attached to the said board, substantially as herein set forth. y

3. The combination with the strings and the bridge of a piano-forte, of astrip of channeled metal the edges of which bear upon the strings, and screws for clamping the said strip upon the strings, substantially as herein set forth.

4. The combination with the strips and the bridge of a piano-forte, of a channeled strip of aluminium the edges of which bear upon the strings, and screws for clamping the said strip upon the strings, substantially as herein set forth.

5. The combination with a pianoforte string and the pins to which the ends of said string are attached, of a spring interposed between one end of the string and its attaching pin and serving for the attachment of the string to the pin, substantially as herein set forth.

ALEXANDER WILFORD HALL.

Witnesses:

HENRY T. BROWN, FREDK. HAYNEs.

IOO

IIO 

